Diaphragm



A. F. R. COTTON.

` DIAPHRAGM.

APPLICATION FILED FES. 8,1921

1,417,718, Patented May 30,1922.-

-F1g1. ngz. Flg. Figa.

ARTHUR. FREDERICK RIcHMoND corro-N, or LONDON, ENGLAND.

To all. 'whom-,it concern:

Be it known `that I, ARTHUR FREDERICK 'RICHMOND Co'i'roN, aBritish-subject, residing at la Chesterfield' Street, Mayfair, L on-ldon,Fingland, have invented certain new and useful Improvements inDiaphragms, of

which the following is a specification;

vThis invention relates to vibratory diapliragmsv for' telephonereceivers, for the sound boxes4 of gramophonesand the like,

DIAPHBAGM.

Specication of Letters Patent. Patented luay 30,' 1922.

s, i921. serial No. 443,331.

tained the best results by employing a woven linen fabric of the kindknown as tracing Cloth. A y

The fabric -is Cut into discs of suitable size, and is applied to acelluloid sheet or disc b preferably thicker (Figure 2), which .istreated with aeroplane dope, acetoneV or like solvent; the/,twojuxtaposed materialsv (see Figure 3) are preferably subjected to slightpressure,.whereby the softened Celluandfor other similar purposes, andconsist/s. loid is caused to penetrate the textile mateof an improveddiaphragm suitable both for the preparation of sound records and for thereproduction ofV sound `by .records or other means. The main object is.to provide a diaphragm with no .musical note or fre- -quency of its ownand thereby to eliminate resonance effects due to the actual material ofthe diaphragm.

According to the 'present invention, Vthe discforming .the diaphragm iscomposed of one or more layers of woven or other fabric Aof textilematerial which is or are stiifened lposed discs ready for pressure. f

Figure 5 illustrates a frame\liolding the by` impregnation withCelluloid by means of asuitable solvent of the latter.

A4The invention ,is hereafter more fully described withl reference totheaccompanying drawings, inwhich f .t

Figures 1 and 2 represent ,suitable discs of linen `and celluloidrespectively for the construction .of thel diaphragm.

Figures 3 and 4 show sections of the j uxtatextile material beforeapplication of the Celluloid disc.

Figure 6 representsl in section the coml pleted diaphragm ready formounting.v

Figure 7 is an elevationl of a Completed diaphragm suitable for atelephone receiver.

Figure 8 is a section of the same.

- Figure) is an'elevation of a diaphragm for the soundbox of agramophone.

Figure 10 is a part sectional elevation of the diaphragm fitted -inthesoundbox.

The improved diaphragm A comprises a foundation. Consisting of artextilefabric,

g `which may be of cotton, muslin, linen or silk, and is'stilfened byimpregnation with Celluloid. The fabric may be woven as v .shown by thedisc a iniFigure 1`, or may Consist of superposed layers al a2 ofparallel threads, as shown in Figure 5, where the two layers merelycross one another. I have ob- !UNITEDVSTATES Ai'nrrsla'l A ofi-Tricia.

rial. The solvent lis then removed, its departure being accelerated byartificial drying if desired.

Alternatively4 the linen or like material may be stretched in` asuitable frame c as shown in Figure 5, in which it is gripped aroundlthe periphery by means of clamping nuts cllpressing upon a cover platec2; the solvent is then applied and the celluloid disc b is pressed intocontact with the fabric, as indicated in Figure. 3.. Th@ celluloiddiscsmay be applied on both sides of the fabric a if desired, as shown. inFigure 4. In either case the softened celluloid is Caused to penev`tratethe fabric, resulting in an adherent structure, the section of which isshown in Figure 6. v

In thev case of a telephone receiver, the centre of the diaphragm A isprovided with means for electromagnet operation, such as a disc d ofsoft iron, as seen in Figure 7, to form ay magnetic armaturesuitablysecured in position b-y a rivet d1 and -washer d2 igure 8). i Forgramophone sound boxes and the like, the stylus bar e is -connected tothe' impregnated linen diaphragm LA (Figure 9) by I means of two washersor nuts e1 c2 upon av Central pin 'or rivet es passing ,through thediaphragm, as shownin' Figure 10, 4or kby means of a screw which piercesthe diaphragm and is secured to the stylus bar.

I have found by experiment that dia- .phragms constructed' as abovedescribed pos- 'the ordinary type.' .By using Celluloid of ductionswithl gramophone diaphragme of greater thickness than the textile thelatter becomes entirely immersed Within the cellu-v,

loid.

Having thus described my invention, What I claim as such and desire tosecure by Letters Patent is l. A vibratory diaphragm, composed oftextile fabric stiffened byimpregnation with Celluloid by means of asolvent of the latter.

2. A vibratory diaphragm composed of linen applied to a sheet ofCelluloid which is treated with a solvent of the latter and caused topenetrate the fabric.

3. A vibratory diaphragm, composed of textile fabric and Celluloid, saidCelluloid being caused to impregnate said' fabric.

4. A vibratory diaphragm, composed of textile fabric and Celluloid, saidCelluloid being softened by means of a solvent and While thus softenedcaused to impregnate said fabric.

5. A vibratory diaphragm, comprising a foundation of vtextile materialand a layer thereinto.

6. A vib'ratory diaphragm, consisting of a -foundation of textilematerial, and a covering of Celluloid, said Celluloid being treated witha solvent and Caused to impregnate said textile material, beingthereafter freed from said solvent byVV evaporation caused by drying. I7. A diaphragm for the soundboxes of gramophones, comprising a' discmade of tracing linen, layers of Celluloid applied to both sides of saiddisc, said layers of celluloid being treated with aeroplane dope andsubjected to pressure against said disc.'

In testimony whereof Lhereunto aiix my signature.

ARTHUR FREDERICK" RICHMOND COTTON.

